Technique to determine instantaneous piston skirt friction during piston slap

The intermittent transient contact of the piston skirt and cylinder liner is related to the secondary motion of the piston. The instantaneous piston secondary motion measured using laser displacement sensors can indicate whether the piston skirt is in contact with the cylinder liner. The force of the impacting piston skirt on the cylinder liner can be calculated using the equation of motion, which allows the piston skirt friction force to be distinguished from the total friction force and friction torque. The results showed that the piston skirt friction force contributes as much as 44% of the overall piston assembly friction force.